Test 1 Flashcards

Question

Glutathione oxidized vs reduced form

Answer 1

It consists of the amino acids Proline, Glycine and Hydroxyproline coiled together

Answer 2

1. Translation on the ribosome 2. hydroxylation of pro and lys 3. release from ribosome 4. glycosylation 5. triple helix formation 6. secretion from cell 7. removal of N- and C- terminal domains 8. crosslink formation

Answer 3

Hemeproteins: oxygen transport and storing (hemoglobin, myoglobin); O2 activation for oxidation electron transfer as a part of the electron transport chain

Answer 4

Reversible binding of O2 to the skeletal structure of the heme prosthetic group.

Answer 5

The ability of myoglobin and hemoglobin to bind oxygen depends on the presence of a heme molecule. When oxygen concentration in muscles falls to low levels, myoglobin releases its oxygen, thus functioning as an oxygen “battery” that delivers oxygen fuel when needed and holding onto it under all other conditions.

Answer 6

Hemoglobin is derived from the myoglobin protein 500 million years ago the myoglobin gene duplicated and part of the gene became hemoglobin 100 million years later, the hemoglobin gene duplicated again forming α and β subunits.

Answer 7

HbA1 HbA2 HbF HbA1C

Answer 8

O2 is bound more tightly with myoglobin than with hemoglobin. pO2 needed for half saturation (50% binding) of myoglobin is about 1 mm Hg (1 Torr) compared to about 26 mm Hg for hemoglobin.

Answer 9

One molecule of hemoglobin (with four hemes) can bind with four molecules of O2 .

Answer 10

Tense and relaxed states

Answer 11

CO2 is an allosteric inhibitor of hemoglobin. CO2 is bound to the N-terminal amino acids of hemoglobin The combination of CO2 with NH2 groups is called a carbamate.

Answer 12

The regulations of O2 binding by H+ and CO2 The binding of oxygen to hemoglobin decreases with increasing H+ concentration (lower pH) or when the hemoglobin is exposed to increased partial pressure of CO2 (pCO2 ). primarily responsible for the release of O2 from the oxyhemoglobin to the tissues.

Answer 13

2,3-BPG is produced as an intermediate of glycolysis. It specifically binds to deoxyhemoglobin (and not to oxyhemoglobin) and decreases the O2 affinity to Hb (facilitates the release of O2 from the Hb)

Answer 14

inherited disorders - affects shape of red blood cells In sickle cell anemia, some red blood cells are shaped like sickles or crescent moons. These sickle cells also become rigid and sticky, which can slow or block blood flow In HbS, the nonpolar amino acid valine has replaced the polar surface residue glutamate in position 6 of the β subunit, generating a hydrophobic “sticky patch” on the surface of the β subunit of deoxyHbS.

Answer 15

genetic defects - result from partial or total absence of one or more α or β chains of hemoglobin. most common genetic blood disorder characterized by decreased hemoglobin production (anemia). Over 750 different mutations have been identified.

Answer 16

define the boundaries of all cells asymmetric, sheetlike structures.

Answer 17

Prevents unwanted molecules from diffusing inside the cells Allows the cell to take up specific molecules and remove unwanted one external cell membrane internal membranes

Answer 18

usually contain an even number of carbon atoms (typically 12–20) Monounsaturated fatty acids contain one carbon-to-carbon double bond. Polyunsaturated fatty acids contain two or more carbon-to-carbon double bonds

Answer 19

have only single bonds

Answer 20

Have one or more double bonds

Answer 21

Phosphoglyceride a phospholipid

Answer 22

Sphingomyelin phospholipid and a sphingolipid

Answer 23

Cerebroside Sphingolipid and a glycolipid

Answer 24

Sphingolipids, sphingomyelins

Answer 25

Glycolipids, cerebrosides

Answer 26

Cholesterol, characterized by four fused carbon rings. One of cholesterol’s functions is to reduce the fluidity of the membrane. To do so, it forms strong interactions with phospholipids using its rigid steroid ring structure

Answer 27

Different treatments have to be applied to remove proteins from the lipid membrane pH change -> peripheral detergent, enzymes -> integral

Answer 28

Most transmembrane proteins are embedded in the membrane using α-helices composed of nonpolar amino acids Glycophorin

Answer 29

proteins located on the surface of the cell membrane that are covalently attached to lipids embedded within the cell membrane.

Answer 30

can be formed from b-strands

Answer 31

proteins containing glycans attached to amino acid side chains

Answer 32

describes the structure of the plasma membrane as a mosaic of components —including phospholipids, cholesterol, proteins, and carbohydrates—that gives the membrane a fluid character

Answer 33

the process by which a chemical or physical signal is transmitted through a cell as a series of molecular events

Answer 34

Net transport via diffusion only occurs when there is a concentration gradient.

Answer 35

does not require energy to move substances across cell membranes.

Answer 36

Many important transport systems function to move molecules against a concentration gradient. This is known as active transport. Because such movement is unfavorable and brings the system further from equilibrium, active transport must be coupled to a process that provides energy.

Answer 37

the movement of molecules or ions across a cell membrane from a region of lower concentration to a region of higher concentration—against the concentration gradient

Answer 38

Channels - ion channels allow ions to flow rapidly across membranes down the gradients Carriers - utilize the gradient of one ion to drive the transport of another against its gradient Pumps - energy transducers in that they convert one form of free energy into another.